Needle bar clamp



April 19, 1955 w. A. AYRES NEEDLE BAR CLAMP Filed Dec. 12, 1951 2 INVENTOR.

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United States Patent NEEDLE BAR CLAMP Waldemar A. Ayres, Lakewood, Ohio, assignor to White Sewing Machine Corporation, Cleveland, Ohio, a corporation of Delaware Application December 12, 1951, Serial No. 261,186 2 Claims. (Cl. 112-226) This invention relates to an improved and novel needle bar clamp for a sewing machine.

An object of the invention is to provide an improved needle bar clamp construction for a sewing machine which is simple, which utilizes a minimum number of easily produced parts, which can be readily and inexpensively formed and mounted on the needle bar and which assures the correct angular and axial positioning of the needle in the needle bar.

Further and additional objects and advantages not hereinbefore specified will become apparent hereinafter during the detailed description of embodiments of the invention which is to follow and which embodiments are illustrated in the accompanying drawing wherein,

Fig. l is an enlarged partial elevational and partial sectional view of a needle bar for a sewing machine equipped with the needle bar clamp according to the present invention, the needle being shown clamped in the needle bar and illustrated in elevation.

Fig. 2 is a view partly in bottom section taken along the line 22 of Fig. 1 direction of the arrows.

Fig. 3 is a transverse sectional view taken substantially on line 3-3 of Fig. 1 looking in the direction of the arrows, and

Fig. 4 is an enlarged fragmentary partial elevational and partial longitudinal sectional view of a needle bar for a sewing machine equipped with the needle bar clamp according to another embodiment of the present invention, the needle being shown in elevation clamped in the needle bar.

The needle bar of a sewing machine is indicated at 10, it being understood that said needle bar is mounted for vertical reciprocation in the sewing machine head as is conventional and therefore not illustrated or further referred to herein. The lower end of the needle bar is provided with a cylindrical bore 11 of such length as to enable the needle to be inserted therein to the proper axial or longitudinal position. The diameter of the bore 11 is correlated to the diameter of the mounting shank of the needle and to the chordal width of the longitudinally extending flat provided on the needle shank as will later be explained. The bore 11 is capable of being expeditiously formed in the bar by a simple drilling operation.

The needles employed in sewing machines ordinarily are provided on their shanks with longitudinally extending chordal flats to enable the needles to be inserted in their needle bar clamps in the proper angular position. Accordingly the needle bar 10 of the present invention is provided adjacent the lower end of the bore 11 with key means extending radially of the bore 11 and cooperating with the flat on the shank of the needle and assuring the proper angular positioning of the needle when it is This key means may take various plan and partly in looking in the inserted into the bore. forms, a simple one of which is that illustrated in the drawings wherein the lower end of the needle bar 10 is provided with a lug-like element 12 extending radially into the bore 11 and formed by peening a portion of the end of the needle bar radially inwardly of the bore 11 by means of a peening tool. The peening tool forms a groove 13 in the end of the needle bar to provide material for displacement radially inwardly of the bore 11 to constitute the lug 12 and said groove 13 may be filled with solder and ground smooth in finishing the bar.

The needle has an attaching or mounting shank 14 of such length that when the needle is fully inserted into bore and opening is screwed the threaded shank Patented Apr. 19, 1955 the bore 11 with the upper end of the shank 14 engaging the upper end of the bore 11 the needle will be in the proper axial or longitudinal position as respects the distance of the needle eye 15 from the lower end of the needle bar. The attaching shank 14 of the needle is provided with a longitudinally extending chordal flat 16 and when the shank is inserted into the bore 11 this flat must be disposed toward the lug 12, thus assuring the proper angular positioning of the needle.

The lower end of the needle bar 10 is of reduced external diameter to provide a reduced end upon which the member 17 mounting the clamping screw is fixedly secured. The member 17 extends from the needle bar 10 toward the vertical standard of the gooseneck of the sewing machine head as will be well understood and is utilized for the securing of attachments to the needle bar, as also will be well understood. The member 17 is provided with a threaded bore aligned with an opening in the reduced lower end of the needle bar and into which threaded 8 o screw. The outer end of the screw is proknurled head 19 to facilitate its turning in the needle in the bore 11 of the the clamping vided with a clamping and unclamping needle bar 10.

When it is desired to insert a needle in the needle bar the clamping screw is backed off and the attaching or mounting shank 14 of the needle is inserted into the bore 11 with the fiat 16 of the shank adjacent to the lug 12. The needle is inserted until the upper end of the shank engages the upper end of the bore 11 and then the clamping screw is screwed to clamping position wherein the inner end of the screw is firmly pressing against the curved surface of the shank 14 of the needle. It will be noted that there is clearance between the circumference of the shank 14 of the needle and the bore 11. The diameter of the bore-11 and the diameter of the shank 14 of the needle, as well as the chordal width of the flat 16, are so correlated that when the edges 20 of the flat 16 are firmly contacting the wall of the bore 11, as shown in Fig. 3, under the clamping action of the clamping screw, said shank 14 will be firmly secured in the bore 11. In addition, there is clearance provided between the lug 12 and the flat 16 of such an order that when the corners 20 of the flat 16 are firmly engaging the wall of the bore 11 the flat 16 is still slightly out of contact with the lug 12. Consequently the clamping screw acting on the shank 14 will not tend to tilt the needle about the lug 12 as a fulcrum since the corner edges 20 of the fiat 16 of the needle shank will firmly engage the wall of the bore 11 before the fiat 16 contacts the lug 12. The needle will be clamped in the needle bar in the correct vertical position for proper cooperation with the other mechanism of the sewing machine.

In Fig. 4 there is illustrated an embodiment of the invention wherein the effective longitudinal length of the bore in the needle bar may be adjusted to provide accurate vertical orientation of the needle and the needle eye in respect to the sewing machine hook. In the form shown in Fig. 4 the bore 11 in the lower end of the needle bar becomes, in effect, a counterbore which communicates with a reduced threaded bore 21 formed in the needle bar 10 and having an adjustable externally threaded plug 22 screwed therein and provided centrally on its end within the counterbore 11 with a slot 23 which receives the pointed inner end of the mounting shank 14 of the needle and which also serves as a slot for an adjusting tool inserted through the counterbore 11 to adjust the plug 22. It will be understood that the plug 22 is adjusted accurately to correctly position the end of the plug in the counterbore 11 so that when the mounting shank of the needle is inserted into the bore 11 its pointed end will contact the end of the plug 22 and assure the correct longitudinal orientation of the eye 15 of the needle with respect to the sewing machine hook.

The plug 22 may be secured in adjusted position by any suitable means, one of which is shown in Fig. 4 as the setscrew 24 mounted in the needle bar and engaging the plug 22.

In some instances the chordal flat on the mounting shank of the needle may be diametrically reversed from the position of the chordal flat shown in the drawings and it will be understood that if the needle to be used in the needle bar is so formed that then the radial lug 12 will be in the diametrically opposite position from that shown in the drawing and on the same side of the needle bar as is the clamping screw 18.

In the arrangement last referred to the clamping screw 18 contacts the chordal flat and presses the curved surface of the mounting shank of the needle into engagement with the wall of the bore 11 with a clearance existing between the flat of the shank and the lug 12.

Although preferred embodiments of the invention have been illustrated and described herein it will be understood that the invention is susceptible of various modifications and adaptations within the scope of the appended claims.

Having thus described my invention, I claim:

1. In combination, a sewing machine needle having a mounting shank of predetermined length and diameter and provided with a longitudinally extending chordal flat; a needle bar adapted to be mounted in a sewing machine head for vertical reciprocation and provided at its lower end with a longitudinally extending cylindrical bore of a length less than the length of the mounting shank of the needle and of a diameter such that when the longitudinal edges of the chordal flat of the needle shank engage the wall of the bore the needle shank diametrically opposite to said chordal fiat will be spaced from the wall of the bore, said bar having at its lower end key means extending radially into said bore a predetermined distance and cooperating with the longitudinally extending chordal flat to assure correct angular positioning of the shank in the bore, and a clamping screw carried by said bar inwardly of the lower end thereof and of said key means and located at the diametrically opposite side of the bore from said key means, whereby when clamping engagement of said screw with said mounting shank has caused tight engagement of the longitudinal edges of said chordal flat with the wall of said bore a clearance exists between said wall and said shank diametrically opposite to said chordal fiat.

2. The combination defined in claim 1 and wherein said key means is a peened lug extending radially inwardly of the lower end of the bore.

References Cited in the file of this patent UNITED STATES PATENTS 121,967 Secor Dec. 19, 1871 527,915 Wheeler Oct. 23, 1894 1,896,047 Grieb Jan. 31, 1933 2,036,959 Rubel Apr. 7, 1936 FOREIGN PATENTS 457,717 France July 19, 1913 

